U.S. patent number 7,595,857 [Application Number 11/478,553] was granted by the patent office on 2009-09-29 for method of fabricating liquid crystal display device.
This patent grant is currently assigned to LG Display Co., Ltd.. Invention is credited to Jun-Beom Cho, Jae-Kyun Lee, Jung Il Lee, Myoung-Su Yang.
United States Patent |
7,595,857 |
Yang , et al. |
September 29, 2009 |
Method of fabricating liquid crystal display device
Abstract
A method of fabricating a liquid crystal display device
includes: preparing a first substrate in which a plurality of first
panels is formed; preparing a second substrate in which a plurality
of second panels is formed; forming a seal pattern around an outer
edge of the panel, the seal pattern defining an active region and a
dummy region and having at one side a protruding portion extending
to the dummy region; dropping liquid crystal more than the
reference amount to the active region; bonding the first and second
substrates together by the seal pattern; separating a plurality of
liquid crystal panels by cutting the first and second substrates,
the liquid crystal panels being formed by bonding the first and
second panels; and removing surplus liquid crystal from the liquid
crystal panel by pressurizing the liquid crystal panel.
Accordingly, image quality deterioration due to an insufficient or
excessive amount of provided liquid crystal is prevented by forming
the protruding portion at the seal pattern and removing the surplus
liquid crystal from the liquid crystal panel or providing liquid
crystal through the protruding portion.
Inventors: |
Yang; Myoung-Su (Gyeonggi-Do,
KR), Lee; Jae-Kyun (Gyeonggi-Do, KR), Lee;
Jung Il (Seoul, KR), Cho; Jun-Beom (Gyeonggi-Do,
KR) |
Assignee: |
LG Display Co., Ltd. (Seoul,
KR)
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Family
ID: |
38184437 |
Appl.
No.: |
11/478,553 |
Filed: |
June 30, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070146622 A1 |
Jun 28, 2007 |
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Foreign Application Priority Data
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Dec 23, 2005 [KR] |
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10-2005-0129077 |
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Current U.S.
Class: |
349/187; 349/189;
349/154; 349/153 |
Current CPC
Class: |
G02F
1/1341 (20130101); G02F 1/1339 (20130101); G02F
1/13415 (20210101) |
Current International
Class: |
G02F
1/1339 (20060101); G02F 1/13 (20060101); G02F
1/1341 (20060101) |
Field of
Search: |
;349/189 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1442738 |
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Sep 2003 |
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CN |
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59-231516 |
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Dec 1984 |
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JP |
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Primary Examiner: Le; Uyen-Chau
Assistant Examiner: Chu; Chris
Attorney, Agent or Firm: McKenna Long & Aldridge
Claims
What is claimed is:
1. A method of fabricating a liquid crystal display device,
comprising: preparing a first substrate; preparing a second
substrate, the first substrate and the second substrate including a
plurality of predefined unit panel regions; forming a seal pattern
within each of the predefined unit panel regions on one of the
first and second substrates, the seal pattern having an active
pattern and a dummy pattern, wherein the dummy pattern protrudes
from the active region; dispensing liquid crystal in the predefined
unit panel regions on one of the first and second substrates;
bonding the first and second substrates together using the seal
pattern; cutting the bonded first and second substrates into unit
panels corresponding the predefined unit panel regions; forming an
aperture in the seal pattern by bursting the thinned portion of the
dummy pattern by pressurizing the at least one unit panel; removing
surplus liquid crystal from the at least one unit panel through the
aperture to adjust the amount of liquid crystal in at least one
unit panel; and encapsulating the aperture.
2. The method of claim 1, wherein the cutting the first and second
substrates includes forming an aperture in the seal pattern by
cutting part of the dummy pattern of the seal pattern.
3. The method of claim 2, wherein the adjusting the amount of
liquid crystal includes removing surplus liquid crystal from the at
least one unit panel through the aperture by pressurizing a surface
of the at least one unit panel.
4. The method of claim 3, further comprising encapsulating the
aperture.
5. The method of claim 4, wherein the encapsulating of the aperture
comprises: injecting a seal material to the aperture; and hardening
the seal material.
6. The method of claim 2, wherein the adjusting the amount of
liquid crystal includes injecting a predetermined amount of liquid
crystal to at least one unit panel through the aperture.
7. The method of claim 6, further comprising encapsulating the
aperture.
8. The method of claim 7, wherein the encapsulating of the aperture
comprises: injecting a seal material to the aperture; and hardening
the seal material.
9. The method of claim 1, wherein the cutting the first and second
substrates includes thinning a section of the dummy pattern by
partially cutting the dummy pattern to provide a thinned portion of
the dummy pattern.
10. The method of claim 9, wherein the thinned portion of the dummy
pattern has a thickness such that the thinned portion is burst when
pressure is applied to the at least one unit panel.
11. The method of claim 1, wherein the encapsulating of the
aperture comprises: injecting a seal material to the aperture; and
hardening the seal material.
12. The method of claim 1, wherein preparing the first substrate
includes forming a plurality of thin film transistors on the first
substrate and preparing the substrate includes forming a color
filter on the second substrate.
13. The method of claim 12, wherein the seal pattern is formed on
the first substrate.
14. The method of claim 12, wherein the liquid crystal is dispensed
onto the second substrate.
15. A method of fabricating a liquid crystal display device,
comprising: preparing a first substrate; preparing a second
substrate, the first substrate and the second substrate including a
plurality of unit panel regions; forming a seal pattern
substantially along an outer edge of the unit panel regions, the
seal pattern having a protruding portion extending to one side of
the seal pattern; dispensing liquid crystal more than a
predetermined reference amount to the panel regions; bonding the
first and second substrates by the seal pattern; hardening the seal
pattern; separating the bonded first and second substrates into a
plurality of liquid crystal panels by cutting the first and second
substrates outside edges of the seal pattern except the protruding
portion of the seal pattern and cutting the protruding portion;
discharging a portion of liquid crystal from the liquid crystal
panel through the cut protruding portion; and encapsulating the cut
protruding portion using an encapsulating material.
16. The method of claim 15, wherein the first substrate is a thin
film transistor array panel, and the second panel is a color filter
substrate.
17. A method of fabricating a liquid crystal display device,
comprising: preparing a first substrate; preparing a second
substrate, the first substrate and the second substrate including a
plurality of unit panel regions; forming a seal pattern
substantially along an outer edge of the unit panel regions, the
seal pattern having a protruding portion extending to one side of
the seal pattern; dispensing liquid crystal more than a
predetermined reference amount to the panel regions; bonding the
first and second substrates by the seal pattern; hardening the seal
pattern; separating the bonded first and second substrates into a
plurality of panels by cutting the first and second substrates
outside edges of the seal pattern, wherein the protruding portion
is cut such that part of the protruding portion of the seal pattern
remains; forming an aperture by bursting the remaining part of
protruding portion of the seal pattern by pressurizing the liquid
crystal panel; discharging a portion of the liquid crystal from the
liquid crystal panel through the aperture; and encapsulating the
aperture by using an encapsulating material.
18. The method of claim 17, wherein the part of the protruding
portion has a thinner after said.
Description
This application claims the benefit of the Korean Application No.
2005-129077 filed on Dec. 23, 2005, which is hereby incorporated by
reference for all purposes as if fully set forth herein. This
application incorporates by reference co-pending application Ser.
No. 10/184,096, filed on Jun. 28, 2002 entitled "SYSTEM AND METHOD
FOR MANUFACTURING LIQUID CRYSTAL DISPLAY DEVICES FROM LARGE MOTHER
SUBSTRATE PANELS"; and co-pending application Ser. No. 10/184,096,
filed on Jun. 29, 2006, entitled "METHODS OF MANUFACTURING LIQUID
CRYSTAL DISPLAY DEVICES" for all purposes as if fully set forth
herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display (LCD)
device using a dispensing method, and more particularly, to a
method of fabricating a liquid crystal display device capable of
improving image quality by preventing gravity defects in liquid
crystal display.
2. Description of the Background Art
With the recent development of various portable electronic devices
such as a mobile phones, PDAs, notebook computers, light and thin
flat panel display devices are increasingly demanded. Research is
actively ongoing on such flat panel display devices including
liquid crystal displays (LCDs), plasma display panels (PDPs), field
emission displays (FEDs), vacuum fluorescent displays (VFDs) and
the like. Of those devices, the LCD devices are drawing much
attention because of the ability to be mass produced, the
relatively easy operation of their driving units, and their
implementation of high image quality.
FIG. 1 is a schematic cross-sectional view of a general LCD device.
As illustrated in the drawing, an LCD device 1 includes a lower
substrate 5, an upper substrate 3, and a liquid crystal layer 7
formed between the lower and upper substrates 5 and 3. The lower
substrate 5 is a driving device array substrate. Although not
illustrated in the drawing, a plurality of pixels are formed on the
lower substrate 5, and a driving device, such as a thin film
transistor (TFT) is formed in each pixel. The upper substrate 3 is
a color filter substrate and includes a color filter layer for
implementing actual colors. Also, a pixel electrode and a common
electrode are formed on the lower substrate 5 and the upper
substrate 3, respectively, and alignment layers are applied thereon
to align liquid crystal molecules of the liquid crystal layer
7.
The lower substrate 5 and the upper substrate 3 are bonded together
by a sealing material 9, and the liquid crystal layer 7 is formed
therebetween. Thus, the liquid crystal molecules are driven by the
driving device formed on the lower substrate 5 to control the
transmittance of light passing through the liquid crystal layer,
thereby displaying information.
A process of fabricating an LCD device may be divided into a
driving device array substrate process for forming driving devices
on the lower substrate 5, and a color filter process and a cell
process for forming a color filter on the upper substrate 3. Such
processes for the LCD will now be described with reference to FIG.
2.
In the driving device array process, a plurality of gate lines and
data lines are arranged on the lower substrate to define pixel
areas, and a TFT (for example) connected to the gate and data lines
is formed in each of the pixel areas (S101). Also, in the driving
device array process, a pixel electrode is formed that is connected
to the TFT to drive the liquid crystal layer upon receiving signals
through the TFT.
Also, in the color filter process, a red, green and blue (RGB)
color filter layer and common electrodes are formed on the upper
substrate 3 (S104).
Then, alignment layers are applied on the upper and lower
substrates 3 and 5, respectively, and then the alignment layers are
rubbed to provide an alignment controlling force or a fixing
surface (i.e., a pretilt angle and an alignment direction) to the
liquid crystal molecules of the liquid crystal layer formed between
the upper and lower substrates 3 and 5 (S102, S105). Thereafter,
spacers are dispersed onto the lower substrate to maintain a
uniform cell gap, a sealing material is applied along an outer edge
of the upper substrate 3, and then the lower and upper substrates 5
and 3 are pressurized and bonded (S103, S106, S107).
The bonded lower substrate 5 and the upper substrate 3 are formed
form large-sized glass substrates. That is, a plurality of panel
regions are formed in each large-sized glass substrate, and a TFT
and a color filter layer are formed in such panel regions,
respectively. For this reason, in order to fabricate each
individual liquid crystal panels, the glass substrates should be
cut and processed (S108). Thereafter, a liquid crystal is injected
through a liquid crystal injection hole into each liquid crystal
panel processed in the aforementioned manner to form the liquid
crystal layer. Then, the liquid crystal injection hole is
encapsulated or "plugged", and then the liquid crystal panel is
examined, thereby fabricating an LCD device (S109, S110).
Here, the injecting of the liquid crystal is achieved by the
following processes. That is, as illustrated in FIG. 3, a nitrogen
gas (N2 gas) is supplied into a vacuum chamber in a state where an
injection hole 16 of a liquid crystal panel 1 is in contact with
the liquid crystal, and thus a degree of vacuum of the chamber 10
is lowered. Then, the liquid crystal 14 is injected into the panel
1 by the difference between the internal pressure of the liquid
crystal panel 1 and the pressure of the vacuum chamber 10. After
the panel 1 is completely filled with the liquid crystal, the
injection hole 16 is encapsulated by an encapsulating material,
thereby forming a liquid crystal layer (This type of injection
method is called a vacuum injection method of liquid crystal).
However, disadvantageously, it takes a long time to inject liquid
crystal into a panel through the injection hole 16. That is, only a
very small amount of liquid crystal is injected into the liquid
crystal panel per unit time because this is only a very small gap
of just a few micrometers (.mu.m) between the driving device array
substrate and the color filter substrate of the liquid crystal
panel. For example, when a liquid crystal panel of approximately 15
inches is fabricated, it takes approximately 8 hours to complete
the injection of liquid crystal. Such injection of liquid crystal
over a long period of time delays the fabrication process of the
liquid crystal panel, and thus deteriorates fabrication efficiency.
Particularly, the vacuum injection method is inadequate for a
large-sized liquid crystal panel because the time it takes to
inject liquid crystal increases as liquid crystal panels become
larger.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a method of
fabricating a liquid crystal display device that substantially
obviates one or more of the problems due to limitations and
disadvantages of the related art.
Therefore, an advantage of the present invention is to provide a
method of fabricating a liquid crystal display (LCD) device capable
of improving processing efficiency of the LCD device by dropping
liquid crystal directly onto a large-sized glass substrate
including at least one panel region, and uniformly distributing the
dropped liquid crystal over the entire panel region by a bonding
pressure of a liquid crystal panel to thereby form a liquid crystal
layer quickly.
Another advantage of the present invention is to provide a method
of fabricating an LCD device capable of preventing gravity
inferiority of liquid crystal by forming a protruding portion of
the seal pattern extending to a dummy region from one side of a
seal pattern, dropping an amount of liquid crystal on a glass
substrate, discharging or injecting liquid crystal through the
protruding portion that has been cut or thinned in a cutting
process, and encapsulating the cut protruding portion.
To achieve these and other advantages and in accordance with the
purpose of the present invention, as embodied and broadly described
herein, there is provided a method of fabricating a liquid crystal
display device, comprising preparing a first substrate; preparing a
second substrate, the first substrate and the second substrate
including a plurality of predefined unit panel regions; forming a
seal pattern within each of the predefined unit panel regions on
one of the first and second substrates, the seal pattern having an
active pattern and a dummy pattern, wherein the dummy pattern
protrudes from the active region; dispensing liquid crystal in the
predefined unit panel regions on one of the first and second
substrates; bonding the first and second substrates together using
the seal pattern; cutting the bonded first and second substrates
into unit panels corresponding the predefined unit panel regions;
and adjusting the amount of liquid crystal in at least one unit
panel.
The separating of the plurality of liquid crystal panels by cutting
the first and second substrates includes forming an aperture by
cutting part of the dummy pattern of the seal pattern. In the
adjusting of the amount of liquid crystal, surplus liquid crystal
filled in the liquid crystal panel is removed through the aperture
by pressurizing the liquid crystal panel. Also, in the adjusting of
the amount of liquid crystal, a predetermined amount of liquid
crystal is injected into the panel through the aperture.
Further, the method of fabricating a liquid crystal display device
according to this invention may includes preparing a first
substrate; preparing a second substrate, the first substrate and
the second substrate including a plurality of unit panel regions;
forming a seal pattern substantially along an outer edge of the
unit panel regions, the seal pattern having a protruding portion
extending to one side of the seal pattern; dispensing liquid
crystal more than a predetermined reference amount to the panel
regions; bonding the first and second substrates by the seal
pattern; hardening the seal pattern; separating the bonded first
and second substrates into a plurality of liquid crystal panels by
cutting the first and second substrates outside edges of the seal
pattern except the protruding portion of the seal pattern and
cutting the protruding portion; discharging a portion of liquid
crystal from the liquid crystal panel through the cut protruding
portion; and encapsulating the cut protruding portion using an
encapsulating material.
In another aspect of the present invention, a method of fabricating
a liquid crystal display panel includes preparing a first
substrate; preparing a second substrate, the first substrate and
the second substrate including a plurality of unit panel regions;
forming a seal pattern substantially along an outer edge of the
unit panel regions, the seal pattern having a protruding portion
extending to one side of the seal pattern; dispensing liquid
crystal more than a predetermined reference amount to the panel
regions; bonding the first and second substrates by the seal
pattern; hardening the seal pattern; separating the bonded first
and second substrates into a plurality of panels by cutting the
first and second substrates outside edges of the seal pattern,
wherein the protruding portion is cut such that part of the
protruding portion of the seal pattern remains; forming an aperture
by bursting the remaining part of protruding portion of the seal
pattern by pressurizing the liquid crystal panel; discharging a
portion of the liquid crystal from the liquid crystal panel through
the aperture; and encapsulating the aperture by using an
encapsulating material.
In another aspect of the present invention, a method of fabricating
a liquid crystal display device includes preparing a first
substrate; preparing a second substrate, the first substrate and
the second substrate including a plurality of unit panel regions;
forming a seal pattern substantially along an outer edge of the
unit panel regions, the seal pattern having a protruding portion
extending to one side of the seal pattern; dispensing liquid
crystal more than a predetermined reference amount to the panel
regions; bonding the first and second substrates by the seal
pattern; hardening the seal pattern; separating the bonded first
and second substrates into a plurality of panels by cutting the
first and second substrates outside edges of the seal pattern,
wherein the protruding portion is cut such that part of the
protruding portion of the seal pattern remains; forming an aperture
by bursting the remaining part of protruding portion of the seal
pattern by pressurizing the liquid crystal panel; discharging a
portion of the liquid crystal from the liquid crystal panel through
the aperture; and encapsulating the aperture by using an
encapsulating material.
In another aspect of the present invention, a liquid crystal
display device includes a first substrate having a plurality of
thin film transistors thereon; a second substrate separated from
the first substrate by a cell gap and bonded to the first substrate
by a seal pattern; liquid crystal in the cell gap; wherein the seal
pattern includes a first portion and a second portion, wherein the
second portion protrudes from the first portion and includes two
substantially parallel parts extending laterally from the first
portion having an encapsulation material therebetween.
It is to be understood that both the foregoing general description
and the following detailed description are exemplary and
explanatory and are intended to provide further explanation of the
invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further
understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention.
In the drawings:
FIG. 1 is a cross-sectional view of a general LCD device;
FIG. 2 is a flow chart of the related art method of fabricating an
LCD device;
FIG. 3 is a view illustrating injection of liquid crystal according
to the related art LCD device;
FIG. 4 is a view illustrating a LCD device fabricated by a liquid
crystal dispensing method;
FIG. 5 is a flow chart illustrating a method of fabricating the LCD
device according to the present invention;
FIG. 6 is a schematic plan view of a thin film transistor array
substrate and a color filter substrate defined into panel regions
and a dummy region;
FIG. 7A is a view illustrating a process of dropping liquid crystal
on a color filter substrate;
FIG. 7B is a view illustrating a process of forming a seal pattern
on a thin film transistor arrays substrate;
FIG. 8 is a cross-sectional view illustrating a bonding process of
the thin film transistor array substrate and the color filter
substrate formed by FIGS. 7A and 7B;
FIGS. 9A and 9B are a plan view and a cross-sectional view,
respectively, illustrating a separating and pressurizing a
plurality of liquid crystal panels;
FIGS. 10A and 10B are a plan view and a cross-sectional view,
respectively, illustrating an encapsulating process; and
FIG. 11 is a view illustrating a seal pattern protruding portion of
an LCD device prior to a cutting process and a unit panel after the
cutting process according to another embodiment of the present
invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Reference will now be made in detail to the embodiments of the
present invention, examples of which are illustrated in the
accompanying drawings.
FIG. 4 is a view illustrating a basic concept of a liquid crystal
dispensing method. As illustrated in the drawing, in the liquid
crystal dispensing method, liquid crystal 107 is dropped or
dispensed onto a lower substrate 105 before the lower substrate 105
and an upper substrate 103, respectively having a thin film
transistor (TFT) and a color filter (CF), are bonded together. The
liquid crystal 107 may be dropped onto the substrate 103 having the
color filter. That is, in the liquid crystal dispensing method, the
liquid crystal may be dropped onto any one of both TFT and CF
substrates. However, the substrate onto which the liquid crystal
has been dropped should be placed under the other substrate at the
time of bonding of the two substrates.
Here, a seal pattern 109 is applied around an outer edge of the
upper substrate 103, so that the upper substrate 103 and the lower
substrate 105 are bonded together by applying pressure thereto. At
the same time, liquid crystal drops 107 are spread widely by the
pressure, thereby forming a liquid crystal layer between the upper
and lower substrates 103 and 105. That is, such a liquid crystal
dispensing method is particularly characterized in that the bonding
of a panel 101 using a seal pattern 109 is performed after liquid
crystal 107 is dropped onto the lower substrate.
A method of fabricating the LCD device using such a liquid crystal
dispensing method is different from a fabrication method adopting
the related art liquid crystal injection method. In the related art
liquid crystal injection method, after a large-sized glass
substrate having a plurality of panel regions is divided into
individual panels, injection of liquid crystal is performed. In
contrast to this related art method, in the liquid crystal
dispensing method, liquid crystal is previously dropped onto a
substrate to thereby form a liquid crystal layer, and then the
glass substrate can be processed and separated into individual
panels. Such process differences provide many advantages in
fabricating an actual LCD device. Of course, as for those
advantages, some occur due to the liquid crystal dispensing method
itself (i.e., rapid generation of a liquid crystal layer), and some
occur because a liquid crystal layer is formed in a unit of a glass
substrate having a plurality of panel regions. This will now be
described in detail by taking the case where four panel regions are
formed in a glass substrate as an example. In the liquid crystal
injection method, when liquid crystal is injected into four
processed liquid crystal panels, the liquid crystal panels having
the same cell gaps can be formed only under the same conditions
(e.g., the same liquid crystal container, the same injection
pressure, etc.). However, in the liquid crystal dispensing method,
four processed liquid crystal panels having different cell gaps may
be formed by controlling the amount of liquid crystal being dropped
onto the liquid crystal panels at once.
In contrast, in the liquid crystal dispensing method, the liquid
crystal is dropped onto the substrate through a liquid crystal
dispenser. When cell gaps of liquid crystal panels having lower
substrates made from one large-sized glass substrate are to be
different from one another, the amount of liquid crystal dropped
onto each of the panel regions should be precisely and individually
controlled, which causes inconvenience. Furthermore, in the liquid
crystal dispensing method, the amount of liquid crystal dropped
onto the panel regions may be less or more than the set reference
amount. Here, the set reference amount refers to the amount of
liquid crystal that can be filled in a cell gap region of a liquid
crystal panel.
Also, in such liquid crystal dispensing method, a seal pattern is
formed in a closed pattern along an outer edge of a panel region
and then bonding into a liquid crystal panel is made after the
liquid crystal is dropped. For this reason, both additional
injection of liquid crystal and removable of surplus liquid crystal
cannot be performed even when the amount of liquid crystal provided
to the panel region is less or more than the set reference
amount.
Therefore, the present invention provides a method of fabricating
an LCD device capable of particularly solving those problems by
forming a seal pattern that can allow removal of surplus liquid
crystal from a liquid crystal panel. That is, a protruding portion
is formed that protrudes outward from one side of the seal pattern,
and a sufficient amount of liquid crystal is dropped onto the
substrate. In a process of separating liquid crystal panels after
bonding of the panel, the protruding portion of the seal pattern is
cut to thereby form an aperture, and the surplus liquid crystal is
removed through the aperture.
FIG. 5 is a view illustrating a flow chart of a fabrication process
of an LCD device employing the aforementioned liquid crystal
dispensing method. FIGS. 6 to 10B are views illustrating a specific
fabrication method according to the process order. Accordingly, the
method of fabricating an LCD device according to the present
invention will now be described with reference to FIG. 5 and FIGS.
6 to 10B.
As illustrated in FIGS. 5 and 6, substrate 200 having panel regions
210 and dummy regions 230 are defined are prepared. Then, a TFT and
a color filter layer (not shown), driving devices and electronic
components of the different substrates 200 are formed through a TFT
array process and a color filter process, respectively (S201,
S202). The TFT array process and the color filter process may be
the same as those described above with reference to FIG. 2, and are
collectively performed on large-sized glass substrates 200
including a plurality of panel regions 210. Particularly, because
the present fabrication method employs the liquid crystal
dispensing method, it can be effectively applied to a larger glass
substrate (e.g., a large glass substrate having an area of more
than 1000.times.200 mm2).
Then, alignment layers are respectively applied onto a thin film
transistor array substrate including the TFT and a color filter
substrate including the color filter layer, and then rubbing is
performed thereon (S202, S205). The liquid crystal is dropped or
dispensed in the panel region on the thin film transistor array
substrate, and the seal pattern is formed along an outer edge of
the panel region on the color filter substrate (203,S306).
Alternately, the liquid crystal may be dropped in the panel region
of the color filter substrate and the seal pattern may be applied
along an outer edge of the panel region of the thin film transistor
array substrate. Also, the dispensing of liquid crystal and the
applying of the seal pattern may be performed on one substrate.
FIGS. 7A and 7B are detailed views illustrating processes of
dispensing liquid crystal and forming a seal pattern. As
illustrated in FIG. 7A, in the liquid crystal dispensing process, a
liquid crystal dispenser 220 is placed above a color filter
substrate 200a, and then liquid crystal 250a is dropped to a
desired region, namely, a panel region, while the substrate 200a is
moving. In the present example it is assumed that the amount of
liquid crystal 205a dropped to the panel region 210a is more than
the set reference amount, so that a cell gap region is over-filled
with liquid crystal.
As illustrated in FIG. 7B, a seal pattern 300 is formed along a
panel region 210b of a thin film transistor array substrate 200b.
Here, one side of the seal pattern 300 extends out of the panel
region 210b. That is, a protruding portion 350 extending out of the
panel region 210b and protruding to a dummy region 230 is formed at
one side of the seal pattern 300.
As described above, the liquid crystal 250a is dropped onto the
color filter substrate 210, and the seal pattern 300 is formed on
the thin film transistor array substrate 210b. Then, the color
filter substrate 210a and the thin film transistor array substrate
210b are aligned. In this state, the two aligned substrates 210a
and 210b are pressurized to be bonded together by the seal pattern
300, and, at the same time, the dropped liquid crystal is
substantially uniformly distributed over the entire panel by the
pressurization (S207). In such a manner, a plurality of liquid
crystal panels each having liquid crystal layers is formed in the
large-sized glass substrate (the lower substrate and the upper
substrate) (S207).
FIG. 8 is a cross-sectional view of the liquid crystal panel. As
illustrated therein, a liquid crystal layer 250 formed between the
color filter substrate 200a and the thin film transistor array
substrate 200b may have a thickness greater than a set thickness of
a cell gap. This may occur because a surplus of liquid crystal
(more than the reference amount) is dropped during dispensing of
the liquid crystal.
Then, the bonded substrates are processed and cut into a plurality
of liquid crystal panels (S208). That is, as illustrated in FIG.
9A, the plurality of liquid crystal panels are separated along a
cutting line of the substrate 200. Here, the protruding portion of
the seal pattern 300 is also cut so that an aperture 370 is formed
at one side of the seal pattern.
Here, as illustrated in FIG. 11, the protruding portion 350 of the
seal pattern may be formed in part along the cutting line, and the
detailed description thereon will be made later.
Thereafter, the surplus liquid crystal is removed through a
pressurizing process (S209). That is, as illustrated in FIG. 9B,
the surplus liquid crystal to the liquid crystal layer 250 is
removed through the aperture 370 by pressurizing the color filter
substrate 200a and the thin film transistor array substrate 200b,
so that the liquid crystal layer has the same height as the set
height of a cell gap.
It is also possible to inject liquid crystal through the aperture
370 to add liquid crystal to the liquid crystal layer if the cell
gap has been underfilled.
After the removal of the surplus liquid crystal, the aperture is
encapsulated by an encapsulating material, thereby completing an
LCD device (S210). That is, as illustrated in FIGS. 10A and 10B,
the cut region of the seal pattern 300 is encapsulated or "plugged"
by an encapsulating material 400, thereby fabricating the LCD
device.
The encapsulation using the encapsulating material 400 is performed
by injecting a seal material into the aperture and hardening
it.
Accordingly, the method of fabricating the LCD device by the liquid
crystal dispensing method makes processes simpler than those of the
fabrication method using the related art liquid crystal injection
method. Thus, the method according to the present invention may
improve fabrication efficiency and achieve a high production
yield.
In the method of fabricating the LCD device according to the
present invention, a protruding portion protruding to a dummy
region is formed at one side of a seal pattern, and the protruding
portion is cut during the process of separating a liquid crystal
panel, thereby forming a seal pattern having an aperture at one
side of a liquid crystal panel. Also, surplus liquid crystal is
removed from the liquid crystal panel, so that a liquid crystal
layer has the same height as a desired cell gap size, so that image
quality degradation may be prevented that is caused by an
insufficient or excessive amount of liquid crystal.
An LCD device employing a general liquid crystal dispensing method
has advantages of a quick manufacturing process. However, such an
LCD device may have an image-quality degradation problem due to an
insufficient or excessive amount of liquid crystal when an
incorrect amount of liquid crystal is removed. Particularly,
because it is difficult to precisely control the amount of liquid
crystal according to a cell gap, the amount of liquid crystal
should be controlled in every liquid crystal panel according to a
model of the LCD device. Particularly, in the case of a multi-model
glass substrate, the amount of liquid crystal should be controlled
for each individual panel region which may be inconvenient.
Therefore, in the present invention, when liquid crystal is
dropped, a surplus amount of liquid crystal more than the reference
amount may be dispensed and then the surplus liquid crystal is
removed. Thus, an accurate amount of liquid crystal may be provided
to a liquid crystal panel without causing any of the aforementioned
problems. Also, as described above, this becomes possible by
forming a protruding portion at a seal pattern that protrudes to
the dummy region. That is, in an operation of separating a
plurality of liquid crystal panels after bonding of the liquid
crystal panel, an aperture is formed at one side of the seal
pattern by cutting the protruding portion, and the surplus liquid
crystal is removed through the aperture. Also, liquid crystal may
be further injected to the panel through the aperture.
However, in the present invention described above, a pressure
difference between the liquid crystal layer and the outside of the
liquid crystal panel occurs because the aperture is formed by
completely removing the protruding seal pattern portion, which may
cause bubbles to occur in the liquid crystal layer from the outside
through the aperture.
Therefore, in order to minimize the bubble generation in the liquid
crystal layer, the present invention may prevent the liquid crystal
layer from being exposed to the outside as much as possible by
allowing a part of the protruding portion of the seal pattern to
remain by partially removing the protruding portion.
That is, as illustrated in FIG. 11, the protruding portion of the
seal pattern partially remains on the substrate after the cutting
process, so that an internal pressure of the liquid crystal can be
maintained. Thereafter, the remaining portion of the seal pattern
300' is opened, punctured or burst, and at the same time, surplus
liquid crystal can be removed through the burst region of the seal
pattern.
In such a manner, bubble generation due to the pressure difference
between the liquid crystal layer and the outside can be prevented
by allowing a part of the seal pattern to remain, instead of
completely removing the protruding portion of the seal pattern and
forming an aperture in the cutting process. That is, when the
protruding seal pattern is completely removed in the cutting
process to form the aperture, the liquid crystal layer is exposed
to the outside through the aperture before and until the
pressurizing process Thus the pressure difference between the
liquid crystal layer and the outside may cause bubbles to occur in
the liquid crystal layer from the outside through the aperture.
Therefore, in the present embodiment, a part of the protruding
portion of the seal pattern remains during the cutting process, so
that the liquid crystal layer is not exposed to the outside right
until just before the pressurizing process. Thus, the internal
pressure of the liquid crystal layer can be retained. Also, the
remaining protruding portion of the seal pattern is burst by the
pressure applied to the liquid crystal panel during the
pressurizing process, and, at the same time, an aperture is formed
and the surplus liquid crystal is removed through this region.
Accordingly, bubbles are prevented from being generated in the
liquid crystal layer between the cutting process and the
pressurizing process.
As described so far, in an LCD device fabricated using the liquid
crystal dispensing method according to the present invention, a
seal pattern is formed to have a protruding portion to a dummy
region, and a part of the protruding portion of the seal pattern is
cut in a cutting process for separating a liquid crystal panel to
thereby form an aperture. Thus, surplus liquid crystal within the
liquid crystal panel may be removed through the aperture, or,
liquid crystal may be injected into the liquid crystal panel
through the aperture. Accordingly, when the liquid crystal is
dispensed in the present invention, a surplus amount of liquid
crystal more than the reference amount may be dispensed, and a seal
pattern encapsulating process of encapsulating the aperture may be
additionally performed.
Furthermore, in the present invention, a part of the protruding
portion of the seal pattern may remain in the cutting process,
thereby retaining an internal pressure of the liquid crystal layer
even after the cutting process. Accordingly, bubbles can be
effectively minimized or prevented from being introduced into the
liquid crystal layer from the outside.
In the present invention, both the removal of surplus liquid
crystal from and additional supply of liquid crystal to the liquid
crystal panel may be performed through the aperture formed by
pressurizing the liquid crystal panel.
As described so far, an LCD device is fabricated through a liquid
crystal dispensing method according to the present invention, so
that productivity can be improved through simplified fabrication
processes.
Also, according to the present invention, surplus liquid crystal is
removed from the liquid crystal panel or liquid crystal is further
provided to the liquid crystal panel through a seal pattern
protruding to a dummy region. Thus, gravity inferiority due to an
excessive or insufficient amount of liquid crystal provided in a
liquid crystal panel can be prevented, and thus image quality of an
LCD device can be improved.
It will be apparent to those skilled in the art that various
modifications and variation can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
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